Depression in Singapore: failure to demonstrate an age effect on clinical features

Studies comparing older and younger depressed patients have variably identified differing and similar clinical feature patterns, an inconsistency requiring clarification and explanation. If influential, age may have a true phenotypic effect or be a secondary influence reflecting depressive sub-type differences. If age is primarily influential, then, after controlling for depressive sub-type differences its effect should impact on clinical features - even in non-western regions.

We therefore undertook a study in Singapore, comparing 42 elderly and 28 younger patients of a Singapore psychiatric hospital, and with the diagnostic sub-type profile similar across the age-based groups.

Despite the elderly group being some 35 years older, both at first episode and when surveyed, and having a distinctly higher rate of physical disorders, few clinical differences were identified. While the elderly group reported a less severe depressed mood and more 'somatic' symptoms, analyses indicated that such differences were accounted for by education and language factors, and were compatible with the view that Chinese subjects historically report depression more 'somatically'.

We conclude that, in a non-western, largely Chinese sample of depressed patients, few differences in the phenotypic expression of depression were identified, perhaps reflecting similar distributions of depressive sub-types across the groups, an issue which may have muddied interpretation of western studies.